Well...I may have an answer...

All of the angst from yesterday's post kept me up till nearly 4am...but I may have found an answer to the problem. It's not yet a complete answer, but it kicks that can down the road to Book Three. Here's what I got:

How did Brendan get to his Aunt and Uncle's?

He is about to leave Derry, on his own, when he is caught in a horrific car bomb. His left arm is dislocated and 3 ribs broken, lacerations on his face and head, and a concussion. His rucksack was still on his back when the bomb went, which kept him from being more severely injured. Still had his passport and money. 

The car was left in place by two friends of his--Danny who's also cut up but not badly, and Colm. It wasn't supposed to explode until much later. They rush Brendan away to a safe house on the border, near Strabane, and send word to his mother. She comes and fights to keep him alive against those in the Provisional IRA who want to bury him. She contacts her sister and brother in law, in Houston and they agree to take him. PIRA goes along with it so long as he will stay away.

He's slipped across the border south of Strabane and held in a farm house near Drumcroy. A doctor is brought in and finds he's suffering from Akinetic Catatonia and his heart is acting up. He needs time to heal from his wounds and near heart attack. Aunt Mari and Uncle Sean use their money and connections to give Brendan that time. 

He's provided a passport under the name Brennan McGabbhin, thanks to a farming accident that killed a man and injured his son, in Donegal. That was nearly a year ago, but it's still usable. Aunt Mari travels over to take him from the Irish Republic to Houston. He gets a 3 month medical visa due to heart and emotional problems, then an extension, then overstays. 

So the story in Derry becomes: Brendan Kinsella has left to find work, as verified by a note and money left behind for his mother. And while there are rumors he's dead, no one really knows. Ma even tells his brothers and sister she thinks he's probably run afoul of PIRA and is buried somewhere. Mairead, his married sister in Toronto, has an idea of what really happened but plays along to keep Brendan safe.

And Brendan, now Brennan, is exiled.

I still haven't worked out why Ma protects him after being so nasty to him for so long, but I have ideas. We'll have to see what comes up in Book Three.